Great empires require great gods and great religions. The original gods of natural forces, life, and death that had been adequate for Mesopotamian and Egyptian cities 3,000 years before were no longer adequate for empires spanning millions of people in multiple ethnic groups. Just as governance had to be systematized to cover the new world order, so did the gods and religions, since they are an integral part of such governance. Those doing the governing derived part of their authority from the gods.
